Move all typecasting code to individual screens.

chrome/browser/chromeos/login/enrollment/auto_enrollment_check_screen.h

Index: chrome/browser/chromeos/login/enrollment/auto_enrollment_check_screen.h
diff --git a/chrome/browser/chromeos/login/enrollment/auto_enrollment_check_screen.h b/chrome/browser/chromeos/login/enrollment/auto_enrollment_check_screen.h
index a3e604553c935239452f72bba81a6e12030ce5be..1c924dab3b3edae32f6930d6b641923e700dea6d 100644
--- a/chrome/browser/chromeos/login/enrollment/auto_enrollment_check_screen.h
+++ b/chrome/browser/chromeos/login/enrollment/auto_enrollment_check_screen.h
@@ -15,6 +15,7 @@
 
 namespace chromeos {
 
+class ScreenManager;
 class ScreenObserver;
 
 // Handles the control flow after OOBE auto-update completes to wait for the
@@ -32,6 +33,8 @@ class AutoEnrollmentCheckScreen
       AutoEnrollmentCheckScreenActor* actor);
   virtual ~AutoEnrollmentCheckScreen();
 
+  static AutoEnrollmentCheckScreen* Get(ScreenManager* manager);
+
   // Hands over OOBE control to this AutoEnrollmentCheckStep. It'll return the
   // flow back to the caller via the |screen_observer_|'s OnExit function.
   void Start();